In today's society there exist many different monitoring systems which based on an array of different sensors identify an appropriate function to execute based on the received sensor signals.
Monitor systems are becoming increasingly popular for monitoring areas of special interest. Such systems may be surveillance systems or monitoring of a care taker.
When installing a sensor system either in an indoor or an outdoor environment there are many different actions that may need to be monitored. Especially so for monitoring of a care taker. This has required the use of many specialized sensors adapted to detect a specific action. Examples may be motion sensor (IR detectors for example) for detecting movement of a person, door and window sensors (for example magnetic switches) for detecting the opening or closing of a door or window, fall sensors (such as accelerometers) for detecting if a person falls, audio sensors for detecting different sounds and heat sensors for detecting an increase in temperature indicating the presence of a human.
For instance, the U.S. Pat. No. 6,002,994 discloses a system where a plurality of different types of sensors is used. Examples are motion sensors, magnetic sensors, infrared sensors to name a few.
This system suffers from that the different sensors need to be mounted or installed in different manners depending on the sensor type. They may also require an accurate and possibly complicated installation to make sure they are properly aligned. They are thus not suitable to be installed by a layperson, and professional installation increases the price of the system often making such a system unavailable to a broader public.
The US patent application US2005/0137465 discloses a similar system and suffers from the same drawbacks.
There is thus a need for a system that is easy to install, simple to set up while still being flexible and which uses as few a number of sensors as possible. Also, there is a need for a sensor system in which the number of different types of sensors used is minimal.